Several studies have shown a major development in height and cannon bone circumference in foals from birth to weaning and from different breeds. However, in Brazil, there is little information about foal development. For this reason, this study has used data on foals from seven different farms in Pernambuco, Northeast Brazil, where horses have a major economic importance. The aim of this study was to compare foal’s development from four breeds and to develop a regression formula in order to estimate such development. It was used data from 210 suckling foals (Arabians n = 18, Campolina n = 86, Mangalarga Marchador n = 42 and Quarter Horses n = 64), raised in similar management practices. Their height at withers, heart girth, and cannon bone girth were measured monthly from birth to weaning. Data we reanalyzed by ANOVA and Tukey Test, with P established in 5%. The highest mean of height at withers was observed in the Arabian foals, and it was similar to Campolina and Mangalarga Marchador foals. The last breed presented a higher percentage of gain in height (~36%) and higher heart girth. On the other hand, Campolina foals had the highest mean of cannon bone girth. There was a significant interaction between breed and development phase in heart and cannon bone girths. All regression for mulas obtained from this data was very significant, and it was showed that they can predict height at withers in the four breeds studied. Heart and cannon bone girths showed medium value of R2 and large significance. It is important to highlight that fetal programing produces significant impact on foal development, even after weaning. So, this study would have observed some more changes if its scope had been extended beyond this phase.